Lamp assembly



P 1965 J. B. SHAW ETAL 3,209,139

LAMP ASSEMBLY Filed March 28, 1962 g; Sheets-Sheet l BIB--2- INVENTORS JOHN B. SHAW R ERTS BY GEORGE G 05 0%.MMbMM ATTORNEYS Sept. 28, 1965 J. a SHAW ETAL 3,209,139

LAMP ASSEMBLY Filed March 28, 1962 g Sheets-Sheet 2 INVENTORE JOHN B. SHAW BY GEORGE G. ROBERTS ATTORNEYS United States Patent 3,209,139 LAMP ASSEMBLY John B. Shaw, 45 Hudson St., Redwood City, Calif., and Ge'orge G. Roberts, 447 Eleanor Drive, Woodside, Calif.

Filed Mar. 28, 1962, Ser. N 0. 183,282 3 Claims. (CL 240-11.2)

This invention relates to an improved lamp assembly. More particularly, it relates to an improvement upon the lamp shown in our Patent No. 3,009,053.

In the lamp of our U.S. Patent No. 3,009,053 the wires in the main cord had to be an expensive high-temperatureresistant heavy-duty type (150 C.) in order to withstand the heat generated at the terminals inside the lamp in the vicinity of the socket. In spite of the ventilation provided in that lamp there is still too much heat to use a lightweight inexpensive type of cord. However, the present invention makes it possible for the main cord to be of relatively light weight and to be inexpensive. Thus, it becomes possible to produce a much less expensive lamp, for one of the main expenses involved in the lamp heretofore reside in the high-temperature heavy-duty electrical wire cord that had to be furnished with it, whereas in the present invention a standard two-wire cord of relative light construction, rated at 60 C., and costing only a frac- 7 tion as much, can be used.

An important result of the invention is that the lamp assembly can be sold separately from the cord and can be shipped separately, or the lamp alone can be shipped and the cord bought independentlly, thereby saving considerable shipping expense since the necessary length of cord is heavier than the lamp assembly.

Another problem solved by the invention is that of meeting government requiremnets. Recently the Coast Guard decided that, because of its weak tensile strength, no more than five feet of high-temperature-resistant cord could be used with a portable lamp used aboard ship. At the same time the requirement that there be no splices in the cord was adhered to. Until the present invention was arrived at, there seemed to be no way to meet these requirements.

Moreover, the Coast Guard and Underwriters Laboratories, Inc. require a polarized circuit for portable lamps so that care must be taken 0t insure that no mistakes can be made in connections that would lead to reversal of polarizations. The present invention solves this problem by assuring that proper polarization is maintained at the connection between the lamp unit and the cord.

Other objects and advantages of the invention will appear from the following description of a preferred form thereof.

In the drawings:

FIG. 1 is a view in elevation and partly in section of a lamp assembly embodying the principles of the invention.

FIG. 2 is a view in horizontal section taken along the line 2-2 in FIG. 1.

FIG. 3 is a view in elevation and in section of the upper portion of the lamp showing the elements embodying the new invention and taken along the line 3-3 in FIG. 2.

FIG. 4 is a view in horizontal section taken along the line 4-4 in FIG. 3.

FIG. 5 is a view in horizontal section taken along the line 55 in FIG. 3.

FIG. 6 is an exploded view in perspective of the lamp assembly of FIG. 3, the high heat wires being omitted.

FIG. 1 shows a lamp assembly 10 generally like that in Patent No. 3,009,053 but incorporating our new invention. In acordance with that patent the lamp assembly 10 includes a metal socket 11 into which the base of a light globe 12 fits. The socket 11 is supported by a socket 3,209,139 Patented Sept. 28, 1965 holder 13 of impact resistant and electrically insulating plastic material, the combination of elements 11 and 13 being known as a lamp holder. The socket holder 13 is secured as by screws 13a at its upper end 14 to a shell or inner shade member 15, which is molded from strong plastic material like or similar to that of the socket 13. The shell 15 has a generally radially extending upper end 16 from which depend three projections 17 that engage the upper end 14 of the socket holder 13 and space it away from the upper end 16 of the shell 15. The portion 16 is provided with a central opening 18, and there are a plurality of ventilating openings 19 around the central opening 18. A nipple 19a extends upwardly from the end 16. The lower end of the shell 15 is flared outwardly to provide an inner shade portion 20 with a rim 21 to which a metal lampguard or cage 22 is secured. An outer shade 23, preferably of plastic but metal in some instances, is supported around the inner shade 20 by suitable means such as an open wound coil spring 24, as shown, or by other suitable means described in our Patent No. 3,009,053.

Also in accordance with that patent, a plastic drip shield 25 is provided in order to protect the globe 12 from pain or other water that might otherWise drop down through the ventilating openings 19. For some uses the drip shield may be integral with the shell or may be omitted, but the drip shield 25 is shown as an annular shell with an axially extending portion 26 and a generally radial shield portion 27 having a downwardly extending lip 28. An annular lower surface portion 29 of the shield 25 abuts the upper end of the radial portion 16 of the shell 15, the nipple 19a of the shell 15 is threaded into a socket 29a, and the shield portion 27 is spaced above the rest of the shell 15 and extends wide of it to provide a channel 30 for the passage of air from the openings 19 into the atmosphere, the hot air flowing generally radially outwardly and downwardly to a level below the rim or lip 28 of the drip shield 25, which preferably lies a substantial distance below the upper ends of the openings 19.

In the present invention, the drip shield 25, which has a central passage 31 therethrough, is provided at its upper end 32 with a plug portion 33 having a pair of prongs 34 and 35 and preferably surrounded by a protective rim 36.

Also according to the principles of this present invention, two short lengths 37 and 38 of high-temperature (e.g., C.) wire, preferably insulated, are clamped in good electrical contact with the bases of the respective prongs 34 and 35 and extend down therefrom through the central passage 31 of the drip shield 25 and through the central opening 18 of the shell 15 to the terminals of the socket 11 in the socket holder 13. The plastic drip shield 25, the plastic shell 15, and the plastic socket holder 13 all help to provide heat insulation, and the openings 19 and channel 30 provide heat dissipation; so the plug 33 is much cooler than the socket 11. Therefore, the upper ends of the wires 37 and 38 are in a much cooler environment than are their lower ends.

The lamp assembly can be completed simply by providing a cord with a socket on the end, into which the prongs 34 and 35 of the plug 33 fit. Various kinds of sockets are suitable, but some types are more suited to retaining the waterproof nature of the assembly. For example, the drawing shows a socket 40 with a lower member 41 and an upper member 42 held together by a screw 39. The lower member 41 may be considered as a double-female baffle or socket and the upper member 42 as a plug, but the unit as a whole merely comprises one form of socket assembly 40 to receive the plug 33.

The lower member 41 has a pair of openings 43 and 44 extending all the way up therethrough, each opening 43, 44 having a narrow lower portion 45 that receives only one of the socket prongs 34 or 35 and a wider upper portion 46 to receive not only the prong 34 or 35 but also a prong 47 or 48 of the upper plug 42, to which the main cord 50-a standard light-duty cord rated at 60 C.-is connected. The prongs 47 and 48 are preferably springy and are forced outwardly by the prongs 34 and 35 to insure good electrical contact at their points.

The rim 36 is provided with a keying recess 51 to receive a keying projection 52 on the lower edge of the socket member 41, thereby assuring proper interlock and orientation of their parts and proper polarization of the cord 50 and its connections, so that the polarized plug 50a on the far end of the cord 50 is correctly connected to the globe 12. Similarly, the member 41 has a keying recess 53 in its upper edge, and the plug 42 has a keying projection 54 that fits into it.

To protect the socket 40 and the plug 33 and the bare wires connected to them, from water and the elements, an upper cap member 55 is provided. The cap 55 has an upper end portion 56 whose central opening 57 tightly grips the cord 50, a gasket 58 being provided and preferably cemented to the cord 50 in order to prevent leakage of any water therethrough. The cap 55 also has an elongated imperforate skirt 60 that extends down over the socket 40, and the rim 36 and seats against an O- ring sealing gasket 61 that is seated on the drip shield 25 at the base of the rim 36. Screws 62 are used to tighten the cap 55 to the drip shield 25 and compress the gaskets 58 and 61. Thus, all the electrical parts are fully protected from the entry of outside moisture, and the lamp assembly can be suspended from the cord 50 with the breaking strength being that of the cord 50. The cord 50 is secured to the plug 42 and so is eflectively isolated from the heat at and near the socket 11. As a result, only the two short pieces 37 and 38 need be high-temperature heat-resistant wire, and standard wire can be used for the cord 50. Preferably, the cap 55 and the socket 40 and the plug 33 (except for the metal prongs) are made from a suitable plastic that is shock-resistant as well as an electrical insulation.

Thus the lamp assembly can be shipped separately from the cord 50, and the cord 50, with the proper socket 40 attached, can be sold as a separate unit.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments andapplications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

We claim:

1. In a lamp assembly having a light-globe socket, a socket holder, a shell having an upper sleeve-like portion with an upper end wall joined to said socket holder and having a central opening and also ventilating openings therethrough, and a drip shield joined to the upper end of said shell and overhanging said ventilating openings and having a central passage therethrough connecting to said central opening, the combination therewith of:

a plug portion on the upper end of said drip shield having prongs extending upwardly therefrom and a rim therearound,

two lengths of high-temperature wire electrically connecting said light-globe socket to said prongs,

a double-female socket above said drip shield and interlocked thereto and having openings receiving said prongs,

a second plug having prongs extending into said doublefemale sockets and into electrical contact with the prongs of said plug portion,

a light-duty electrical cord connected to said second plug and isolated from the heat of said light-globe socket, and having a first gasket cemented thereto,

a protective cap having a central opening tightly sealing against said first gasket and a shell enclosing said second plug, said double-female socket, and said plug portion, and

a second gasket sealing between said cap and said drip shield below and outside said rim.

2. A lamp assembly, comprising an insulated housing having an open bottom end, a top end with ventilated openings, and a central passage,

a light socket supported in said housing,

a drip shield to protect said openings, attached to said top end and providing a central passage aligned with that of said housing, and having an upper end,

male contacts on the upper end of said drip shield,

high-temperature electrical wires connecting said light socket to said male contacts,

a flexible insulated electrical cord having at one end connection means for connecting it to said male contacts and having, adjacent thereto a sealing gasket secured thereto,

a protective cap entirely surrounding and sealing said male contacts and connection means,

gasket means between said cap and said shield, and

clamping means for tightening said cap toward said shield to compress both said gasket means and said sealing gasket so as to prevent the entry of moisture into said cap and to clamp said housing, shield, and cap as an assembly to said cord through said sealing gasket so that the lamp can be suspended from the cord with the strength of suspension that of the breaking strength of the cord.

3. A lamp assembly, comprising an insulating housing having an open and flared bottom end and a top end with ventilated openings, and a central passage,

a drip shield to protect said openings, attached to said top end and providing a central passage aligned with that of said housing, and having an upper end,

a light socket supported in said housing,

polarized disconnectable male contacts on the upper end of said drip shield,

high-temperature electrical wires connecting said light socket to said male contacts,

a flexible polarized electrical cord having a rubberized jacket with a sealing gasket secured thereto and having on one end connection means for connecting it to said male contacts,

a protective cap entirely surrounding and sealing said contacts and connection means,

gasket means between said cap and said shield, and

clamping means for tightening said cap toward said shield to compress said gasket means and said sealing gasket so as to prevent the entry of moisture into said cap and to clamp said housing, shield, cap assembly to said cord through said sealing gasket so that the lamp can be suspended from the cord with the strength of the breaking strength of the cord.

References Cited by the Examiner UNITED STATES PATENTS 890,770 6/08 Hubbell 339- X 2,304,085 12/42 Grifiin 240-1l.3 2,835,790 5/58 Divendal 240-47 2,972,676 2/61 Moser 240-78 3,009,053 11/61 Shaw et al. 240-l1.2 3,109,692 11/63 Stanley 339-184 NORTON ANSHER, Primary Examiner. J. D. BEIN, EVON C. BLUNK, Examiners, 

1. IN A LAMP ASSEMBLY HAVING A LIGHT-GLOBE SOCKET, A SOCKET HOLDER, A SHELL HAVING AN UPPER SLEEVE-LIKE PORTION WITH AN UPPER END WALL JOINED TO SAID SOCKET HOLDER AND HAVING A CENTRAL OPENING AND ALSE VENTILATING OPENINGS THERETHROUGH, AND A DRIP SHIELD JOINED TO THE UPPER END OF SAID SHELL AND OVERHANGING SAID VENTILATING OPENINGS AND HAVING A CENTRAL PASSAGE THERETHROUGH CONNECTING TO SAID CENTRAL OPENING, THE COMBINATION THEREWITH OF: A PLUG PORTION ON THE UPPER END OF SAID DRIP SHEILD HAVING PRONGS EXTENDING UPWARDLY THEREFORM AND A RIM THEREAROUND, TWO LENGTHS OF HIGH-TEMPERATURE WIRE ELECTRICALLY CONNECTING SID LIGHT-GLOBE SOCKET TO SAID PRONGS, A DOUBLE-FEMALE SOCKET ABOVE SAID DRIP SHIELD AND INTERLOCKED THERETO AND HAVING OPENINGS RECEIVING SAID PRONGS, A SECOND PLUG HAVING PRONGS EXTENDING INTO SAID DOUBLEFEMALE SOCKETS AND INTO ELECTRICAL CONTACT WITH THE PRONGS OF SAID PLUG PORTION, A LIGHT-DUTY ELECTRICAL CONNECTED TO SAID SECOND PLUG AND ISOLATED FROM THE HEAT OF SAID LIGHT-GLOBE SOCKET, AND HAVING A FIRST GASKET CEMENTED THERETO, 